/**

* Copyright 2017, Google, Inc.

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

*

* http://www.apache.org/licenses/LICENSE-2.0

*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/

'use strict';

// Require process, so we can mock environment variables

const process = require('process');

// [START app]

const express = require('express');

const Knex = require('knex');

const crypto = require('crypto');

const app = express();

app.enable('trust proxy');

const knex = connect();

function connect () {

// [START connect]

const config = {

user: process.env.SQL_USER,

password: process.env.SQL_PASSWORD,

database: process.env.SQL_DATABASE

};

if (process.env.INSTANCE_CONNECTION_NAME && process.env.NODE_ENV === 'production') {

config.host = `/cloudsql/${process.env.INSTANCE_CONNECTION_NAME}`;

}

// Connect to the database

const knex = Knex({

client: 'pg',

connection: config

});

// [END connect]

return knex;

}

/**

* Insert a visit record into the database.

*

* @param {object} knex The Knex connection object.

* @param {object} visit The visit record to insert.

* @returns {Promise}

*/

function insertVisit (knex, visit) {

return knex('visits').insert(visit);

}

/**

* Retrieve the latest 10 visit records from the database.

*

* @param {object} knex The Knex connection object.

* @returns {Promise}

*/

function getVisits (knex) {

return knex.select('timestamp', 'userIp')

.from('visits')

.orderBy('timestamp', 'desc')

.limit(10)

.then((results) => {

return results.map((visit) => `Time: ${visit.timestamp}, AddrHash: ${visit.userIp}`);

});

}

app.get('/', (req, res, next) => {

// Create a visit record to be stored in the database

const visit = {

timestamp: new Date(),

// Store a hash of the visitor's ip address

userIp: crypto.createHash('sha256').update(req.ip).digest('hex').substr(0, 7)

};

insertVisit(knex, visit)

// Query the last 10 visits from the database.

.then(() => getVisits(knex))

.then((visits) => {

res

.status(200)

.set('Content-Type', 'text/plain')

.send(`Last 10 visits:\n${visits.join('\n')}`)

.end();

})

.catch((err) => {

next(err);

});

});

const PORT = process.env.PORT || 8080;

app.listen(PORT, () => {

console.log(`App listening on port ${PORT}`);

console.log('Press Ctrl+C to quit.');

});

// [END app]

module.exports = app;